In the course of about the last fifteen years, concerted efforts have been made to develop techniques and devices for restoring vision in patients afflicted by certain diseases. In patients suffering from macula degeneration and retinitis pigmentosa, both of which diseases lead to a loss of retina function over a period of time and ultimately cause total blindness, it has been discovered that substantial parts of the nervous system of the eye, including the optic nerve and the sub-retinal neurons, actually remain intact and fully functional. Since the early days of research and development in this field, therefore, a number of different techniques and solutions have been proposed for taking advantage of this retained retinal functionality.
One such solution proposes an implant containing photodiodes designed to convert the light incident on the retina into electrical stimuli for the retinal ganglion cells. In practice, however, the energy level of the incident light proved to be insufficient to provoke a depolarization of the nerve cells. An alternative approach has been to capture an image using, for example, a camera and to process the image to match a grid of electrodes positioned on or below the surface of the retina and then to stimulate the nerve tissues via corresponding signals to the electrodes. This latter approach has provided promising results and forms the basis for much on-going research and development in this field.
In German Patent Publication No. DE 10 2006 060045 A1, for example, a system has been proposed in which additional data relating to the relative position in space of the object are processed during the capture and generation of the image signal.
It remains a goal of researchers, however, to develop a visual prosthesis or system that provides patients with an experience of vision that more closely approximates natural sight.